There seems to be a consensus that the need for proteins is increased in the elderly to maintain optimal all the body functions. In several countries, the RDA for proteins has recently been increased to 1g/kg/d for adults over 65 years of age with dietary proteins of good quality. Apart from the quantity to be ingested, which can still remain a problem to reach for this population, the quality of the proteins ingested is essential and involves much more than just the composition of amino acids. The lower the quality of these proteins, the more the quantity to be ingested to meet the AA requirement will be important and therefore difficult to achieve. The quality of a dietary protein is related to its amino acids composition (AA) but also to several other determinants including the speed of digestion, the presence of specific AAs, the food matrix in which the dietary proteins are included and the processes involved in the production of food products (gelation, cooking temperature). The search for alternative protein sources and transitioning towards more sustainable, plant-based nutrition has received much attention in the past decade. But, is this transition compatible with optimal protein nutrition in the elderly? Plant proteins are mostly of low quality in terms of AA composition, digestibility and the presence of anti-nutritional factors. The maintenance of 30% of animal proteins should be considered in the diet to limit the increase of total proteins ingested to 25% above the 1g/kg/d. However, with the increasing number of commercially available proteins isolates, it is now possible to elaborate plant blends competing with animal proteins in terms of nutritional quality. Finally, due to the different life trajectories, inter-individual variability in the response to food intake is high in the elderly and should be studied in order to propose tailored strategies to each older adults phenotype.